Combi-Boiler burst a pipe due to high pressure

[sugarflux]

Hi Can anyone help please?

We have just bought our first flat and it has a combi-boiler. We managed to get it working after a fortnight with no hot water and heating last night. Woke up early this morning to a bang a water pouring from underneath the boiler. It looks like a pipe has burst

When we got the boiler working, the pressure gauge was showing right at the top (above about 4 bars) so could this be the cause? Our friend told us that this just meant the gauge was broken.

The pipe is right at the bottom of the combi boiler and looks like the hole in it should have another pipe coming off but may have been blocked with something. The something it was blocked with is where it is leaking.

If so, can anyone tell me how to reduce the pressure and possibly how to mend the pipe. I'm a complete newby!

Thanks

sugarflux

 

[Plumber Will]

The easiest way to reduce the pressure is by the pressure release valve.......if you don't know where or what it is then loosen the bleed screw on a radiator. You only want 1-1.5 bar pressure max as for the pipe I need more info.

 

[MANDATE]

It sounds from your description that the 'pressure relief valve' has done its job by opening when the pressure is too high, although you would expect the water to be diverted out side. Question is how did it get to 4bar.
Theres not a lot of point in having a gauge if we don't accept what it is telling us, although I do agree we do need some confidence in gauges as to when they were calibrated.
Easiest way to reduce the pressure would be to bleed a radiator if you dont know where to drain valve is.
I take it the leak has stopped if the PRV has re-seated itself or are you saying a pipe has fractured.

 

[sugarflux]

Thanks for your help here. The leak has stopped now because i've turned the water off at the stop cock. The pipe itself hasn't fractured. The pipe comes out of the bottom of the boiler.

There are 5 pipes that go along the bottom (front to back of the boiler). The pipe that is leaking is the fourth from the left. Each of these pipes just go from the inside of the bolier to behind it but the one that is leaking has an extra outlet which points downwards. The pipe has a thread but is left open - ie it looks like it should join on to another pipe.

Is sounds like it could be the pressure relief pipe and that perhaps it should go outside?

If so, is the pipe supposed to just disperse water - should i switch the water back on and let it drain?

Thanks again
sugarflux

 

[oilman]

The resident gas experts will need to know which make and model of boiler you have to give detailed help.

Do you have a manual with the boiler?

If not can you remove the outer cover to see if the pipe goes to a valve with a red knob on?

If it does this pipe is a lot more serious than just a water discharge. It must be capable of discharging boiling water to the outside in a way that avoids injuring someone, so straight out of the wall at head level is definitely a no no. If you're on a higher than ground floor, the pipe must discharge into a metal hopper with metal down pipe.

Another problem you may have is the filling loop valve is leaking and causing water to be continuously fed to the system. The filling loop is almost always left connected, which is illegal. Disconnect this if you can find it and see if the stop valve leaks.

It looks like this

But type this is now illegal and has been superceded by a slightly different type.

 

[sugarflux]

I've had a friend of a friend round to have a look who is a plumber. He said that the boiler will need replacing as it was fitted in 1989 (he found a receipt inside the boiler).

He said the pressure valve is broken and that it is cheaper to replace the boiler than replace the valve as the valve is right at the back.

He also switched the 'loop bit' off so that water is not always fed to the system.

We still have a leak now but it is just a drip and we can keep it on summertime which is just the hot water. turning on the heating seems to make the drip turn into a steady pour so looks like its fan heaters for me until i have saved up enough for a new boiler!

thanks for all your help!
sugarflux

 

[Plumber Will]

What make is it? Saunier duval..Vokera..????

 

[sugarflux]

Saunier Duval....

 

[ChrisR]

Your vendor should have told you that he boiler wasn't working - by law! Get your solicitor to pursue a claim. Get quotes for a replacement, and ask the quoters for a letter explaining that this could not be a new fault.
You are right that there should be a pipe going out from the boilers prv.
If the boiler were not a SD, or it were newer, it would be repairable. SD's are awful.

It sounds like someone had blocked up the prv to stop it dripping. That could have caused a major explosion.

 

[Plumber Will]

If it is the PRV that is now dripping then it would be cheaper to replace the boiler.. as for someone blocking it...it may take some proving?